Study On Integrated Protection Strategy Of Optical Transport Network For High-speed Railway

The optical transport network of high-speed railway is the nerve center of the ground infrastructures of high-speed railway,providing accurate and timely information transmission for emergency operation of trains,dispatching and command,train status monitoring and remote fault diagnosis,and train operation control,etc.In the event of a transmission interruption,it will not only degrade the control system of the high-speed railway train,but also even result in stoppages which will seriously affect the normal operation of the high-speed railway.In order to avoid the huge damage to the railway operation caused by the network failure,this paper does research work on the channel protection and the link protection technologies.The existing channel protection algorithms only use weight as a path-finding index,and the influence of nodes on the path finding results is not considered.The existing P-Cycle circle expansion algorithm only uses the redundancy as an index for limiting the circle expansion,but does not consider the influence of the variance of unprotected working capacity on the extension of the circle.It studies the channel protection technology and P-Cycle protection technology of optical transport network of the high-speed railway respectively and modifies the algorithm of channel protection and P-Cycle circle expansion algorithm and performs algorithm simulation and data analysis.The main research results are as follows:1.In this paper,a routing algorithm BTWH(Balance the Weight and Hop)which minimizes the sum of the total weight of the links and the total number of the nodes is proposed to find the link-disjoint and node-disjoint working path and protection path.BTWH occupies less wavelength resources while balancing the loads,and reducing the protection switching time of the business request when a link failure occurs.Moreover,BTWH can also meet different businesses requests by adjusting the coefficients of the link weight and the total number of nodes.The simulation results show that in the same network,when the businesses requests and the failed links are the same,the BTWH algorithm has better performance than the MTW(Minimum the Total Weight)algorithm in terms of wavelength resource occupancy,protection switching time and average routing hops.2.In this paper,a P-Cycle construction algorithm based on redundancy and variance is proposed and named as RVPA(Redundancy and Variance based P-Cycle Expansion Algorithm),the details are as follows:It creatively calculates the variance of unprotected capacity on the extended candidate circles.When the variance and redundancy are minimized at the same time,the extension circle will be selected as the final circle of this expansion,which effectively limits the number of P-Cycle needed to protect the working capacity of the entire network;The total number of nodes of the extension circle will be limited by comparing the UPL with the redundancy and the parameter M respectively,and the performance under different M values is compared and analyzed.The simulation results show that it can obtain the best result when M equals 0.5,and when the network topology COST239 model has the same free resources and protects the same capacity,the RVPA algorithm is better than POCA(P-Cycle Optimization Configuration Heuristic Algorithm)algorithm in terms of total redundancy,the number of required cycles,protection capacity efficiency and overall algorithm time-consuming.